The primary goal of the Morphology Core is to make available to the investigators of individual projects the expertise, facilities, techniques and technical support required for morphologic and immunolocalization studies of cultured cells and animal and human tissues at both the light and electron microscopic level. The Core supervisor, Dr. Milstone, is an American Board of Pathology certified anatomic pathologist and molecular experimental pathologist with a high level of training and expertise. He will provide consultation to investigators within the Program on interpreting histopathologic changes and identifying optimal procedures for selecting and preparing cells and tissues of experimental animals for morphologic studies. One of the key elements of the Program during the renewal period will be the continued utilization of in vivo and in vitro model systems and reagents, many developed previously within this Program, to investigate molecular regulation and consequences of endothelial-dependent physiologic and pathophysiologic processes. Many of these experimental systems test the effects of under- or over-expressing critical adhesion, activation and/or interaction molecules or cytokines in otherwise "normal" tissues and in models of acute and chronic inflammation and tissue injury. Interpreting these experimental results will depend to a large degree on describing reliably the morphologic changes, including assessing the degree and nature of leukocyte influx and resultant tissue injury, and immunocytochemical localization of the molecules in question. An important function of the Core will therefore be to provide consistent, high quality histology and sensitive methods for immunocytochemical localization. Program studies of intracellular communication events and cell biology will require expanded ultrastructural analysis by both electron and immunoelectronmicroscopy.